nginx: refactor upstream generation

lib.nix

@@ -17,4 +17,64 @@ rec {
     l = firstListenerOfType r w.settings.worker_listeners;
   in connectionInfo l;
 
+  mapWorkersToUpstreamsByType = workerInstances:
+    lib.pipe workerInstances [
+      lib.attrValues
+
+      # Index by worker type
+      (lib.foldl (acc: worker: acc // {
+        ${worker.type} = (acc.${worker.type} or [ ]) ++ [ worker ];
+      }) { })
+
+      # Subindex by resource names, listener types, and convert to upstreams
+      (lib.mapAttrs (_: workers: lib.pipe workers [
+        (lib.concatMap (worker: worker.settings.worker_listeners))
+        lib.flatten
+        mapListenersToUpstreamsByType
+      ]))
+    ];
+
+    mapListenersToUpstreamsByType = listenerInstances:
+      lib.pipe listenerInstances [
+        # Index by resource names
+        (lib.concatMap (listener: lib.pipe listener [
+          (listener: let
+            allResourceNames = lib.pipe listener.resources [
+              (map (resource: resource.names))
+              lib.flatten
+              lib.unique
+            ];
+          in if allResourceNames == [ ]
+            then { "empty" = listener; }
+            else lib.genAttrs allResourceNames (_: listener))
+          lib.attrsToList
+        ]))
+
+        (lib.foldl (acc: listener: acc // {
+          ${listener.name} = (acc.${listener.name} or [ ]) ++ [ listener.value ];
+        }) { })
+
+        # Index by listener type
+        (lib.mapAttrs (_:
+          (lib.foldl (acc: listener: acc // {
+            ${listener.type} = (acc.${listener.type} or [ ]) ++ [ listener ];
+          }) { })
+        ))
+
+        # Convert listeners to upstream URIs
+        (lib.mapAttrs (_:
+          (lib.mapAttrs (_: listeners:
+            lib.pipe listeners [
+              (lib.concatMap (listener:
+                if listener.path != null
+                  then [ "unix:${listener.path}" ]
+                  else (map (addr: "${addr}:${toString listener.port}") listener.bind_addresses)
+              ))
+              # NOTE: Adding ` = { }` to every upstream might seem unnecessary in isolation,
+              #       but it makes it easier to set upstreams in the nginx module.
+              (uris: lib.genAttrs uris (_: { }))
+            ]
+          ))
+        ))
+      ];
 }

synapse-module/nginx.nix

@@ -2,13 +2,10 @@
 let
   cfg = config.services.matrix-synapse-next;
 
-  getWorkersOfType = type: lib.filterAttrs (_: w: w.type == type) cfg.workers.instances;
-  isListenerType = type: listener: lib.lists.any (r: lib.lists.any (n: n == type) r.names) listener.resources;
-  firstListenerOfType = type: worker: lib.lists.findFirst (isListenerType type) (throw "No federation endpoint on receiver") worker.settings.worker_listeners;
-  wAddressOfType = type: w: lib.lists.findFirst (_: true) (throw "No address in receiver") (firstListenerOfType type w).bind_addresses;
-  wPortOfType = type: w: (firstListenerOfType type w).port;
-  wSocketAddressOfType = type: w: "${wAddressOfType type w}:${builtins.toString (wPortOfType type w)}";
-  generateSocketAddresses = type: workers: lib.mapAttrsToList (_: w: "${wSocketAddressOfType type w}") workers;
+  matrix-lib = (import ../lib.nix { inherit lib; });
+
+  workerUpstreams = matrix-lib.mapWorkersToUpstreamsByType cfg.workers.instances;
+  listenerUpstreams = matrix-lib.mapListenersToUpstreamsByType cfg.settings.listeners;
 in
 {
   config = lib.mkIf cfg.enableNginx {
@@ -138,24 +135,17 @@ in
     '';
 
     services.nginx.upstreams.synapse_master.servers = let
-      isMainListener = l: isListenerType "client" l && isListenerType "federation" l;
-      firstMainListener = lib.findFirst isMainListener
-        (throw "No catch-all listener configured") cfg.settings.listeners;
-        address = lib.findFirst (_: true) (throw "No address in main listener") firstMainListener.bind_addresses;
-        port = firstMainListener.port;
-        socketAddress = "${address}:${builtins.toString port}";
-    in {
-      "${socketAddress}" = { };
-    };
+      mainListeners = builtins.intersectAttrs
+        (listenerUpstreams.client.http or { })
+        (listenerUpstreams.federation.http or { });
+    in
+      assert lib.assertMsg (mainListeners != { })
+        "No catch-all listener configured, or listener is not bound to an address";
+        mainListeners;
 
 
     services.nginx.upstreams.synapse_worker_federation = {
-      servers = let
-        fedReceivers = getWorkersOfType "fed-receiver";
-        socketAddresses = generateSocketAddresses "federation" fedReceivers;
-        in if fedReceivers != { } then
-          lib.genAttrs socketAddresses (_: { })
-      else config.services.nginx.upstreams.synapse_master.servers;
+      servers = workerUpstreams.fed-receiver.federation.http or config.services.nginx.upstreams.synapse_master.servers;
       extraConfig = ''
         ip_hash;
       '';
@@ -163,12 +153,7 @@ in
 
 
     services.nginx.upstreams.synapse_worker_initial_sync = {
-      servers = let
-        initialSyncers = getWorkersOfType "initial-sync";
-        socketAddresses = generateSocketAddresses "client" initialSyncers;
-      in if initialSyncers != { } then
-        lib.genAttrs socketAddresses (_: { })
-      else config.services.nginx.upstreams.synapse_master.servers;
+      servers = workerUpstreams.initial-sync.client.http or config.services.nginx.upstreams.synapse_master.servers;
       extraConfig = ''
         hash $mxid_localpart consistent;
       '';
@@ -176,12 +161,7 @@ in
 
 
     services.nginx.upstreams.synapse_worker_normal_sync = {
-      servers = let
-        normalSyncers = getWorkersOfType "normal-sync";
-        socketAddresses = generateSocketAddresses "client" normalSyncers;
-      in if normalSyncers != { } then
-        lib.genAttrs socketAddresses (_: { })
-      else config.services.nginx.upstreams.synapse_master.servers;
+      servers = workerUpstreams.normal-sync.client.http or config.services.nginx.upstreams.synapse_master.servers;
       extraConfig = ''
         hash $mxid_localpart consistent;
       '';
@@ -189,12 +169,7 @@ in
 
 
     services.nginx.upstreams.synapse_worker_user-dir = {
-      servers = let
-        workers = getWorkersOfType "user-dir";
-        socketAddresses = generateSocketAddresses "client" workers;
-      in if workers != { } then
-        lib.genAttrs socketAddresses (_: { })
-      else config.services.nginx.upstreams.synapse_master.servers;
+      servers = workerUpstreams.user-dir.client.http or config.services.nginx.upstreams.synapse_master.servers;
     };
 
     services.nginx.virtualHosts."${cfg.public_baseurl}" = {